Strange Timer Behavior

BlitzMax Forums/BlitzMax Programming/Strange Timer Behavior

Chapman7

(Posted 2016) [#1]


'FRLRT

SuperStrict

'Import "Vec3.bmx"
Import BRL.Timer

AppTitle$ = "Fixed Rate Logic with Render Tweening"

Graphics 800,600

Local newTime:Int = MilliSecs()
Local oldtime:Int = newTime
Local dt# = 1.0/200.00	'100 FPS logic
Local deltaTime#, accumulator#, alpha#, t#

'Local ball:TBody = CreateBody()
'ball.Current.vPos.x = 400
'ball.Current.vPos.y = 500
'ball.Current.vVel.Set(500,-500,0)

SetBlend ALPHABLEND

'Global imgBall:TImage = LoadImage("ball.png")
'MidHandleImage imgBall

Global RenderTween:Int = False

Global SetTime:Int = MilliSecs()
Global GetFPS:Int
Global SetFPS:Int
Global UPS:Int
Global UPSSet:Int

Local ForcedRefreshRate:TTimer

While Not KeyHit(KEY_ESCAPE)
Cls

	If MilliSecs() - SetTime >= 1000
		'Local secondsGone:Float = ((MilliSecs() - SetTime)/1000.0)
		'GetFPS = Int(SetFPS / secondsGone + 0.5)
		GetFPS = SetFPS
		SetFPS = 0
		SetTime = MilliSecs()
		'UPSSet = Int(UPS / secondsGone + 0.5)
		UPSSet = UPS
		UPS = 0
	Else
		SetFPS = SetFPS + 1
	EndIf

	newTime = MilliSecs()
	deltaTime# = (newTime - oldTime) * 0.001
	oldTime = newTime
	
	accumulator :+ deltaTime

	While accumulator >= dt
		UPS = UPS + 1
		'Apply some gravity
		'ApplyLinearForce ball, 0, ball.fMass * 981.0, 0

		'ball.Logic(dt)
		
		accumulator :- dt
		't :+ dt
	Wend

	alpha = accumulator / dt
	
	'ball.Render(alpha)

	If KeyHit(KEY_SPACE) Then RenderTween = 1 - RenderTween
	DrawText "Press the SPACE BAR to turn on render tweening mode.",5,5
	DrawText "RenderTween: "+RenderTween,5,50
	
	DrawText(GetFPS, 0, 70)
	DrawText(UPSSet, 0, 80)
	
	Local Suspended:Byte = AppSuspended()
	
		'If (Suspended = True) Then
			If ForcedRefreshRate = Null Then ForcedRefreshRate = CreateTimer(600.0)
			If WaitTimer(ForcedRefreshRate) > 1 Then Print "yes"
		'Else
		'	If ForcedRefreshRate <> Null Then StopTimer(ForcedRefreshRate)
		'EndIf

	Flip 0     'Eliminates Tearing
Wend
End


Type TBody
	Field fMass:Float = 1.0
	Field Current:TState = New TState
	Field previous:TState = New TState
	
	Method Logic(dt#)
		
		'Basic Linear Physics
		Self.previous = Self.Current.copy()
		Self.Current.vAcc = Self.Current.vForces.DividedByScalar(Self.fMass)
		Self.Current.vVel = Self.Current.vVel.Plus(Self.Current.vAcc.TimesScalar(dt))
		Self.Current.vPos = Self.Current.vPos.Plus(Self.Current.vVel.TimesScalar(dt))
		Self.Current.vForces.Zero()
		
		'Simple Collision
		If Self.Current.vPos.y <= 0 Or Self.Current.vPos.y >= 600
			Self.Current.vVel.y = -Self.Current.vVel.y
		EndIf
		If Self.Current.vPos.x <= 0 Or Self.Current.vPos.x >= 800
			Self.Current.vVel.x = -Self.Current.vVel.x
		EndIf

	End Method
	
	Method Render(alpha#)
		Local x#, y#
		If RenderTween
			x# = Self.Current.vPos.x * alpha + Self.previous.vPos.x * (1.0 - alpha)
			y# = Self.Current.vPos.y * alpha + Self.previous.vPos.y * (1.0 - alpha)
		Else
			x = Self.Current.vPos.x
			y = Self.Current.vPos.y
		EndIf
		'DrawImage imgBall, x, y
	End Method

End Type

Function CreateBody:TBody()
	Return New TBody
End Function

Type TState
	Field vPos:TVec3 = Vec3()
	Field vVel:TVec3 = Vec3()
	Field vAcc:TVec3 = Vec3()
	Field vForces:TVec3 = Vec3()

	Field vAngAcc:TVec3 = Vec3()
	Field vAngVel:TVec3 = Vec3()
	Field vMoments:TVec3 = Vec3()

	Method Copy:TState()
		Local t:TState = New TState
		t.vPos = Self.vPos.Copy()
		t.vVel = Self.vVel.Copy()
		t.vAcc = Self.vAcc.Copy()
		Return t
	End Method
End Type

Function ApplyLinearForce(body:TBody, xf#, yf#, zf#)
	Local vF:TVec3 = Vec3(xf, yf, zf)
	body.Current.vForces = body.Current.vForces.Plus( vF )
End Function



Rem
bbdoc:
EndRem
Type TVec3
	Field x:Float, y:Float, z:Float

	Method Copy:TVec3()
		Return Vec3(Self.x, Self.y, Self.z)
	End Method

	Method CrossProduct:TVec3(v:TVec3)
		Local res:TVec3 = New TVec3
		res.x =  Self.y * v.z  -  Self.z * v.y
		res.y = -Self.x * v.z  +  Self.z * v.x
		res.z =  Self.x * v.y  -  Self.y * v.x
		Return res
	End Method

	Method DividedBy:TVec3(v:TVec3)
		Local res:TVec3 = New TVec3
		res.x = Self.x / v.x
		res.y = Self.y / v.y
		res.z = Self.z / v.z
		Return res
	End Method

	Method DotProduct:Float(v:TVec3)
		Return Self.x * v.x + Self.y * v.y + Self.z * v.z
	End Method

	Method DividedByScalar:TVec3(divisor#)
		Local res:TVec3 = New TVec3
		res.x = Self.x / divisor
		res.y = Self.y / divisor
		res.z = Self.z / divisor
		Return res
	End Method
	
	Method Inverse:TVec3()
		Local v:TVec3 = New TVec3
		v.x = -Self.x
		v.y = -Self.y
		v.z = -Self.z
		Return v
	End Method

	Method Magnitude:Float()
		Return Sqr(Self.x * Self.x + Self.y * Self.y + Self.z * Self.z)
	End Method
	
	Method Minus:TVec3(v:TVec3)
		Local res:TVec3 = New TVec3
		res.x = Self.x - v.x
		res.y = Self.y - v.y
		res.z = Self.z - v.z
		Return res
	End Method
	
	Method Normalize()
		Local m# = Self.Magnitude()
		Self.x :/ m
		Self.y :/ m
		Self.z :/ m
	End Method

	Method Plus:TVec3(v:TVec3)
		Local res:TVec3 = New TVec3
		res.x = Self.x + v.x
		res.y = Self.y + v.y
		res.z = Self.z + v.z
		Return res
	End Method

	Method Set(x#, y#, z#)
		Self.x = x
		Self.y = y
		Self.z = z
	End Method
	
	Method Show(cap:String, xpos:Int, ypos:Int, vspc:Int = 12)
		DrawText cap+".x=" + Self.x,xpos,ypos
		DrawText cap+".y=" + Self.y,xpos,ypos + vspc * 1
		DrawText cap+".z=" + Self.z,xpos,ypos + vspc * 2
	End Method

	Method Times:TVec3(v:TVec3)
		Local res:TVec3 = New TVec3
		res.x = Self.x * v.x
		res.y = Self.y * v.y
		res.z = Self.z * v.z
		Return res
	End Method

	Method TimesScalar:TVec3(scalar#)
		Local res:TVec3 = New TVec3
		res.x = Self.x * scalar
		res.y = Self.y * scalar
		res.z = Self.z * scalar
		Return res
	End Method

	Method Zero()
		Self.x = 0
		Self.y = 0
		Self.z = 0
	End Method

End Type

Rem
bbdoc:
EndRem
Function Vec3:TVec3(x#=0, y#=0, z#=0)
	Local v:TVec3 = New TVec3
	v.x = x
	v.y = y
	v.z = z
	Return v
End Function

I cut out the ball bouncing crap so you guys could run the code easily. When I create a timer with 600 hertz, the FPS is 1000ish and when I create one with 500 hertz, the FPS is 500...

I don't understand what is going on. Ive already rebuilt all my modules

Derron

(Posted 2016) [#2]

That 500 hertz is individual to your computer...

"print" is rather slow ... it additionally slows down your "fast as possible"-tests.

Like explained in the other thread your problem is surely this: the duration of a "wait timer" might lead to clashes with your accumulator.
-> There is not enough time for both, logic and renders with your forces "time slots". So they stumble over each other leading to your FPS cut.

Also there is no reason to disable what I added to your code before: it is there to return "better" FPS/UPS-numbers. The ones you see now are just incorrect (as they are numbers based on 1.x seconds instead of 1.0).

bye
Ron

Chapman7

(Posted 2016) [#3]

Thanks for replying Derron. I just went with the old template to figure out what was wrong with WaitTimer, I am still using your fix with the main thing.

I feel like the 500 hertz thing is just my pc... not sure whats causing it but certain builds produce different results with the exact same code and it's really aggravating.

As for the "time slots" even if they do stumble over each other, how is the WaitTimer locked at 600 but allowing the code to execute faster? (1000 frames per second)


'FRLRT

SuperStrict

AppTitle$ = "Fixed Rate Logic with Render Tweening"

Graphics 800,600

Local newTime:Int = MilliSecs()
Local oldtime:Int = newTime
Local dt# = 1.0/200.00	'100 FPS logic
Local deltaTime#, accumulator#, alpha#, t#

'Local ball:TBody = CreateBody()
'ball.Current.vPos.x = 400
'ball.Current.vPos.y = 500
'ball.Current.vVel.Set(500,-500,0)

SetBlend ALPHABLEND

'Global imgBall:TImage = LoadImage("ball.png")
'MidHandleImage imgBall

Global RenderTween:Int = False

Global SetTime:Int = MilliSecs()
Global GetFPS:Int
Global SetFPS:Int
Global UPS:Int
Global UPSSet:Int

Local ForcedRefreshRate:TTimer

While Not KeyHit(KEY_ESCAPE)
Cls

	If MilliSecs() - SetTime >= 1000
		Local secondsGone:Float = ((MilliSecs() - SetTime)/1000.0)
		GetFPS = Int(SetFPS / secondsGone + 0.5)
		SetFPS = 0
		SetTime = MilliSecs()
		UPSSet = Int(UPS / secondsGone + 0.5)
		UPS = 0
		
		If GetFPS > 601 Then WriteStdout("FPS: " + GetFPS + " SecondsGone: " + secondsGone+"~r~n")
	Else
		SetFPS = SetFPS + 1
	EndIf

	newTime = MilliSecs()
	deltaTime# = (newTime - oldTime) * 0.001
	oldTime = newTime
	
	accumulator :+ deltaTime

	While accumulator >= dt
		UPS = UPS + 1
		'Apply some gravity
		'ApplyLinearForce ball, 0, ball.fMass * 981.0, 0

		'ball.Logic(dt)
		
		accumulator :- dt
		't :+ dt
	Wend

	alpha = accumulator / dt
	
	'ball.Render(alpha)

	If KeyHit(KEY_SPACE) Then RenderTween = 1 - RenderTween
	DrawText "Press the SPACE BAR to turn on render tweening mode.",5,5
	DrawText "RenderTween: "+RenderTween,5,50
	
	DrawText(GetFPS, 0, 70)
	DrawText(UPSSet, 0, 80)
	
	Local Suspended:Byte = AppSuspended()
	
		'If (Suspended = True) Then
			If ForcedRefreshRate = Null Then ForcedRefreshRate = CreateTimer(600.0)
			If WaitTimer(ForcedRefreshRate) > 1 Then WriteStdout("yes")
		'Else
		'	If ForcedRefreshRate <> Null Then StopTimer(ForcedRefreshRate)
		'EndIf

	Flip 0     'Eliminates Tearing
Wend
End


Type TBody
	Field fMass:Float = 1.0
	Field Current:TState = New TState
	Field previous:TState = New TState
	
	Method Logic(dt#)
		
		'Basic Linear Physics
		Self.previous = Self.Current.copy()
		Self.Current.vAcc = Self.Current.vForces.DividedByScalar(Self.fMass)
		Self.Current.vVel = Self.Current.vVel.Plus(Self.Current.vAcc.TimesScalar(dt))
		Self.Current.vPos = Self.Current.vPos.Plus(Self.Current.vVel.TimesScalar(dt))
		Self.Current.vForces.Zero()
		
		'Simple Collision
		If Self.Current.vPos.y <= 0 Or Self.Current.vPos.y >= 600
			Self.Current.vVel.y = -Self.Current.vVel.y
		EndIf
		If Self.Current.vPos.x <= 0 Or Self.Current.vPos.x >= 800
			Self.Current.vVel.x = -Self.Current.vVel.x
		EndIf

	End Method
	
	Method Render(alpha#)
		Local x#, y#
		If RenderTween
			x# = Self.Current.vPos.x * alpha + Self.previous.vPos.x * (1.0 - alpha)
			y# = Self.Current.vPos.y * alpha + Self.previous.vPos.y * (1.0 - alpha)
		Else
			x = Self.Current.vPos.x
			y = Self.Current.vPos.y
		EndIf
		'DrawImage imgBall, x, y
	End Method

End Type

Function CreateBody:TBody()
	Return New TBody
End Function

Type TState
	Field vPos:TVec3 = Vec3()
	Field vVel:TVec3 = Vec3()
	Field vAcc:TVec3 = Vec3()
	Field vForces:TVec3 = Vec3()

	Field vAngAcc:TVec3 = Vec3()
	Field vAngVel:TVec3 = Vec3()
	Field vMoments:TVec3 = Vec3()

	Method Copy:TState()
		Local t:TState = New TState
		t.vPos = Self.vPos.Copy()
		t.vVel = Self.vVel.Copy()
		t.vAcc = Self.vAcc.Copy()
		Return t
	End Method
End Type

Function ApplyLinearForce(body:TBody, xf#, yf#, zf#)
	Local vF:TVec3 = Vec3(xf, yf, zf)
	body.Current.vForces = body.Current.vForces.Plus( vF )
End Function


Rem
bbdoc:
EndRem
Type TVec3
	Field x:Float, y:Float, z:Float

	Method Copy:TVec3()
		Return Vec3(Self.x, Self.y, Self.z)
	End Method

	Method CrossProduct:TVec3(v:TVec3)
		Local res:TVec3 = New TVec3
		res.x =  Self.y * v.z  -  Self.z * v.y
		res.y = -Self.x * v.z  +  Self.z * v.x
		res.z =  Self.x * v.y  -  Self.y * v.x
		Return res
	End Method

	Method DividedBy:TVec3(v:TVec3)
		Local res:TVec3 = New TVec3
		res.x = Self.x / v.x
		res.y = Self.y / v.y
		res.z = Self.z / v.z
		Return res
	End Method

	Method DotProduct:Float(v:TVec3)
		Return Self.x * v.x + Self.y * v.y + Self.z * v.z
	End Method

	Method DividedByScalar:TVec3(divisor#)
		Local res:TVec3 = New TVec3
		res.x = Self.x / divisor
		res.y = Self.y / divisor
		res.z = Self.z / divisor
		Return res
	End Method
	
	Method Inverse:TVec3()
		Local v:TVec3 = New TVec3
		v.x = -Self.x
		v.y = -Self.y
		v.z = -Self.z
		Return v
	End Method

	Method Magnitude:Float()
		Return Sqr(Self.x * Self.x + Self.y * Self.y + Self.z * Self.z)
	End Method
	
	Method Minus:TVec3(v:TVec3)
		Local res:TVec3 = New TVec3
		res.x = Self.x - v.x
		res.y = Self.y - v.y
		res.z = Self.z - v.z
		Return res
	End Method
	
	Method Normalize()
		Local m# = Self.Magnitude()
		Self.x :/ m
		Self.y :/ m
		Self.z :/ m
	End Method

	Method Plus:TVec3(v:TVec3)
		Local res:TVec3 = New TVec3
		res.x = Self.x + v.x
		res.y = Self.y + v.y
		res.z = Self.z + v.z
		Return res
	End Method

	Method Set(x#, y#, z#)
		Self.x = x
		Self.y = y
		Self.z = z
	End Method
	
	Method Show(cap:String, xpos:Int, ypos:Int, vspc:Int = 12)
		DrawText cap+".x=" + Self.x,xpos,ypos
		DrawText cap+".y=" + Self.y,xpos,ypos + vspc * 1
		DrawText cap+".z=" + Self.z,xpos,ypos + vspc * 2
	End Method

	Method Times:TVec3(v:TVec3)
		Local res:TVec3 = New TVec3
		res.x = Self.x * v.x
		res.y = Self.y * v.y
		res.z = Self.z * v.z
		Return res
	End Method

	Method TimesScalar:TVec3(scalar#)
		Local res:TVec3 = New TVec3
		res.x = Self.x * scalar
		res.y = Self.y * scalar
		res.z = Self.z * scalar
		Return res
	End Method

	Method Zero()
		Self.x = 0
		Self.y = 0
		Self.z = 0
	End Method

End Type

Rem
bbdoc:
EndRem
Function Vec3:TVec3(x#=0, y#=0, z#=0)
	Local v:TVec3 = New TVec3
	v.x = x
	v.y = y
	v.z = z
	Return v
End Function

Derron

(Posted 2016) [#4]

I assume that the problem is only apparent if waittimer "steals" too much time.

Rounding issues might happen too.
Like said...create a logger (do not use "print" in the loop) and before exiting print out the results.

Bye
Ron